An image forming apparatus comprises as electrical loads, for example, a charging device that charges a photosensitive drum, a developing device that causes developer to adhere to the charged photosensitive drum, and a transferring device that transfers the developer image onto a print medium. Some image forming apparatuses also comprise a cleaning unit that cleans a belt that conveys a print medium. A high voltage (bias voltage) is applied to these electrical loads via a plurality of connection points from a high voltage power supply. Accordingly, if a terminal breaks or is displaced at any connection point, the connection line from the high voltage power supply to each electrical load may be disconnected. In this case, a normal bias voltage may not be applied to the electrical loads and there is a risk that each electrical load will not work normally.
In view of this, a configuration has been adopted in which one detecting means checks the connection with the high voltage power supply provided for each electrical load.
However, according to the above-described configuration, since the checking means is provided for each electrical load, it is not possible to perform the checking efficiently.